[Distribution characteristics of soil cadmium in different textured paddy soil profiles and its relevance with cadmium uptake by crops].

Adopting atomic absorption spectrometry (novAA400), the present study investigated the distribution characteristics of soil cadmium (Cd) in different textured paddy soil profiles under rice-wheat rotation and its correlation with Cd uptake by rice and wheat in Chengdu Plain through repeatedly taking soil and plant samples at the fixed sites in the field. The results revealed that Cd in the paddy soil profiles was mainly concentrated at the plough layer (0-15 cm) that obviously featured 'Cd accumulates towards the rooting layer'. Soil total Cd and available Cd (1 mol x L(-1) MgCl2 extraction) in the profile declined with soil depths and its average values at 30-45 cm only accounted for 47.

Effects of cadmium stress on alternative oxidase and photosystem II in three wheat cultivars.

The effects of Cd stress (200 micromol/L, 8 days) on respiration and photosynthesis of three wheat cultivars were investigated: Chuanyu 12 (CY12), Chuanmai 42 (CM42), and Chuanmai 47 (CM47). Fifteen-day-old seedlings were exposed to 200 micromol/L CdCl2 for 4 days and 8 days, respectively. The results indicated that Cd was accumulated largely in roots, but little in leaves of all three cultivars.

[Effect of different N, P and K fertilizers on soil pH and available Cd under waterlogged conditions].

In order to tackle the problem of Cd pollution in paddy soils and investigate soil available Cd as affected by different fertilizers, incubation experiments were carried out to study the effects of different N, P and K fertilizers and pH by adding acid or base on soil available Cd under waterlogged conditions. Results revealed that soil pH increased sharply after the soil was flooded, especially at the beginning of incubation, and gradually decreased with incubation time and finally tended to approach the neutral values. The patterns of soil pH change were just opposite to those of soil available Cd, a negative correlation observed between the two.

[Methodology improvement in background elimination in plant Cd measurement by graphite furnace atom absorption].

A problem of higher background value and lower measured Cd value exists when Cd is digested by conventional dry digestion method, measured by graphite furnace atomic absorption, and calculated with peak height numeration. This problem results in difficulty for evaluating samples with Cd contents in the neighborhood of critical values. In order to solve the problem, the present paper focused on background measurement with graphite furnace atomic absorption, modified the pre-preparation procedures of the traditional method, and screened the optimal concentration of the modifier.

Salinity of animal manure and potential risk of secondary soil salinization through successive manure application.

To enhance animal productivity and maximize economic returns, mineral salts are routinely added to animal feed worldwide. Salinity and ionic composition of animal manure from intensive poultry and livestock farms in Guangdong province were investigated. Field experiments were conducted for six successive crops of Brassica Parachinensis to evaluate the possibility of secondary soil salinization by successive application of chicken manure (CM) and pigeon manure (PM) to a garden soil.